The present invention relates to a method and a device for compressing harvested crop material to produce silage in a horizontal silo.
Compression of layered crop material plays an important role in the stability of silage. If, during ensilage, the newly cut crop material is not compressed permanently and thoroughly, residual oxygen becomes enclosed in the individual layers of crop material, which can ultimately result in the growth of undesired organisms such as yeast and fungi, and to improper fermentation, which, in turn, can result in a considerable reduction in the nutritional content of the silage.
Publication DE 75 32 909 makes known a device and a method for compressing green crops laid down in single layers to produce silage in a horizontal silo. To compress the green crop evenly, a roller is supported in a drawbar-type frame, the carrying axle of which is designed as a shaft on which displaceable unbalanced bodies are located. Via a drive element assigned to the shaft, the carrying axle or shaft of the roller body is brought to a high rotational speed, by way of which the entire roller body is set into oscillating motion. When driving over the individual crop material layers, the roller oscillations are transferred to the green crop material, which results in a largely vertical compression of the green crop material.
The disadvantage of this design is that, even though the crop material layers have been compressed, the fact that the “rebound” potential of crop material varies means that pockets of oxygen can remain, which also results in the disadvantages described. Given that the individual layers of crop material can also have hills and valleys, it cannot be ensured—due to the predetermined roller width and the nearly vertical compression—that the hills and valleys will be closed during the rolling process. As such, when the next layer of crop material is laid down, pockets can remain. In addition, since the roller is capable of being driven around its longitudinal axis, it pushes the crop material to be compressed away from the actual compression area.
Publication DE 44 32 823 A1 discloses a device for use with horizontal silos that includes two rotating spreading elements. The device rests—with its underside, at least—on the material to be spread, and the material is spread in the horizontal silo by the rotatably driven spreader. The disadvantage of this design is the fact that the material is spread but not compressed.